The present invention relates to an improved asphalt heating unit for heating existing asphalt paved surfaces, primarily in preparation for joint and seam repair.
The repair of asphalt in streets and other paved areas is a never-ending job. Asphalt becomes deteriorated and pot-holed, and utilities make cuts in the asphalt for accessing utility lines and pipes, requiring frequent repair. In such repair, new asphalt pavement is frequently laid next to old asphalt. The abutment of the old asphalt with the new asphalt creates a seam or joint which needs to be sealed, otherwise the constant flow of traffic and natural elements such as rain and ice will quickly dislodge the asphalt along the seam, creating an unacceptable crack or crevices.
One method used to perform joint and seam repair is simply to pour the new asphalt next to the old and apply joint and seam tacking fluid. However, such a procedure does not always result in a good joint, and is therefore used primarily for quick fixes where a limited lifetime of the paved area is expected. In any case, the tacking fluid is messy, and if it is not used, the new asphalt will be quickly dislodged.
Another method used to repair joint and seams is to heat the existing asphalt adjacent the new asphalt, whereby the old and new asphalt can be mixed to create a homogeneous product in the seam area.
One device used for heating the existing asphalt is an asphalt heater mounted on a trailer to extend from one side of the trailer. The trailer is pulled behind a vehicle which travels along the path of the joint, with the heater positioned over the joint to heat the edge of the old asphalt. The trailer moves at a certain speed, depending upon the BTU output of the heater and the ambient environmental temperature, so that the existing asphalt edge will be sufficiently heated to be mixed with new asphalt being poured. One such device is a Poweray model CS (90A/90/108) Infrared Asphalt Heater.
Since the heater extends only to one side of the trailer, and the trailer normally travels on the existing asphalt and not the new asphalt being poured, whenever the seam makes a 90-degree turn, such as from a longitudinal joint line which travels in the direction of traffic to a transverse joint line cutting across the flow of traffic, the vehicle and trailer must also make a 90-degree turn. The vehicle and trailer sometimes move with the direction of traffic, cut across 90-degrees transverse to the traffic, and then make another 90-degree turn to travel in a direction against the traffic. Having to navigate both a vehicle and a tractor so that the heating element is always over the joint line is usually a cumbersome operation.